Hello Inigo

I have this pool of information about survey. I think it would be enough for start of survey business processes configuration .

Function modules CRM_MKTCA_SURVEY_MKT_PBO and CRM_MKTCA_SURVEY_MKT_PAI do not have the functionality to save the business partner attribute values

http://scn.sap.com/thread/1779132

Create, run and analyze an E-Mail Campaign with a Survey (Part 1)

http://scn.sap.com/community/crm/marketing/blog/2006/07/22/create-run-and-analyze-an-e-mail-campaign-with-a-survey-part-1

Inbound mail processing – Attach files to Opportunity

http://scn.sap.com/community/crm/blog/2005/10/02/inbound-mail-processing-attach-files-to-opportunity

Receiving E-Mail and processing it with ABAP - Version 610 and Higher

http://scn.sap.com/people/thomas.jung/blog/2004/09/09/receiving-e-mail-and-processing-it-with-abap--version-610-and-higher

Survey Parameter XML for http(s)

http://scn.sap.com/thread/1071619

Survey mailer approach

http://scn.sap.com/thread/1814008

Configuration to Track / Evaluate Survey Response

http://scn.sap.com/thread/1831853

Notes

Note 1717324 - Survey Tool: Survey Mailer Servlet

Note 1367567 - CRM Survey:FAQs

Hope it helps

Regards, EL